• Epidemiology
• Sporting injuries
• Statistical review

Finch and Cook1 recently requested feedback on their proposed classification for reinjuries. We applaud them for identifying key challenging areas, and summarising standard statistical approaches to time-to-event data.2–5 Developed within a Bayesian framework, their approach can be applied equally well within a frequentist framework. However, we do not believe their claims that the proposed new classification solves the current analytical challenges. Although we cannot offer solutions at the present time, we do believe the previous classification systems6 ,7 mentioned by Finch and Cook should remain the focus of analytical strategies at this time.

Previous reinjury classifications focused on the previous injury's healing state. If not healed, subsequent injuries are exacerbations. If healed, subsequent injuries are classified according to anatomic location. The proposed classification simply splits each of the previous classification categories6 ,7 into two groups: ‘related to index injury’ and ‘not related to index injury’. The same relationships could be modelled using the previous classifications by simply adding a dichotomous variable (yes/no) called ‘Relation to Index Injury’ in the categorisation scheme. Is including such a variable beneficial?

The …